The present invention relates to an apparatus for molding and applying liners in caps.
According to European patent no. 207385, an apparatus for molding and applying substantially disk-shaped liners in caps are known in the art. This known apparatus comprises a footing, which rotatably supports, so that they are arranged at the vertices of an equilateral triangle and have vertical axes, a carousel for dosing plastic material fed by an extruder, a molding carousel that molds disk-like liners from doses provided by said dosage carousel, and a carousel for inserting the liners in the caps. The doses of plastic material from which the liners are obtained are deposited on disk-like bodies that are conveyed through the various carousels, where the doses are subjected to the molding operations. Hereinafter, for the sake of convenience in description, these bodies are termed shuttles.
The apparatus is completed by a series of four substantially star-shaped elements that can rotate about vertical axes and are provided peripherally with equidistant semicircular recesses that form seats suitable to accommodate said shuttles. Said elements are designated hereinafter as transfer stars. A first star transfers the shuttles from the dosage carousel to the molding carousel, a second star performs transfer from the molding carousel to the insertion carousel, a third star transfers the shuttles from the insertion carousel to the dosage carousel, and a fourth star transfers the caps onto a removal conveyor.
The apparatus thus described has considerable drawbacks caused by the fact that the shuttles, along the regions for transfer from the carousels onto the transfer elements and vice versa, slide on supporting surfaces, undergoing wear and wearing said surfaces.
Another drawback of the known apparatus is its constructive complexity, which is linked to the presence of four shuttle transfer stars. Other drawbacks cause functional limitations that hinder operation of the apparatus at particularly high production rates.
These limitations are due to the fact that the increase in the rotation rate of the various components of the apparatus entails an increase in the centrifugal actions affecting the doses of plastic material deposited on the shuttles; accordingly, these doses are induced to shift radially outward and to escape from the hollows of the shuttles, thus compromising the molding of the liners.
The technical aim of the present invention is to provide an apparatus for molding and applying liners in caps that is capable of transferring the shuttles from one carousel to the other without appreciable friction of the shuttles and of the sliding tracks, so as to improve and extend the efficiency of the apparatus.
Within the scope of this aim, an object of the present invention is to provide an apparatus that uses only three stars interposed between the carousels.
Another object of the present invention is to provide an apparatus in which the doses of plastic material are firmly retained on the shuttles.
Another object of the present invention is to provide an apparatus that is capable of providing effective and easy removal of the plastic liners from the shuttles and of inserting them in the caps.
This aim and these objects are achieved with an apparatus for molding and inserting plastic liners in caps, whose characteristics are defined in the claims.